<!doctype html>
<html ng-app>
    <head>
        <!--<script src="http://code.angularjs.org/angular-1.0.1.min.js"></script>-->
        <script src="angular.js"></script>

    </head>
    <body>
        Your name: <input type="text" ng-model="yourname" placeholder="吴大爷">
        <hr>
        Hello {{yourname || 'Worlddddd'}}!
    </body>
</html>